Filtering low-energy carriers to enhance thermoelectric performance of Cd-doped SnSe via incorporation of MXene sheets

SnSe-based materials have attracted widespread attention in thermoelectrics due to their outstanding thermoelectric performance. However, the pristine and unmodified polycrystalline SnSe reveals poor electrical properties. Doping and constructing nanostructured composite architectures to produce energy filtering effect proved to be an effective method to strengthen thermoelectric performance. In this study, Ti 3 C 2 /Sn 0.98 Cd 0.02 Se composites are successfully fabricated by the solvothermal method combined with the electrostatic self-assembly method and spark plasma sintering. The phase interface introduced by incorporating Ti 3 C 2 into Sn 0.98 Cd 0.02 Se can effectively filter low-energy carriers due to its generation of energy barriers, thereby the Seebeck coefficient of x wt% Ti 3 C 2 /Sn 0.98 Cd 0.02 Se x = (0.05, 0.5, 1) samples is better than that of the pristine Sn 0.98 Cd 0.02 Se over the whole temperature range. Meanwhile, high conductivity was also obtained in 1 wt% Ti 3 C 2 /Sn 0.98 Cd 0.02 Se sample so that the high power factor of 3.31 μWcm −1 K − 2 was acquired at 773 K. Ultimately, a peak ZT value of 0.41 was obtained at 773 K, compared with pristine Sn 0.98 Cd 0.02 Se, and the thermoelectric performance improved by 24%. This study offers an available approach to efficiently enhance the thermoelectric properties of polycrystalline SnSe-based materials.